Abundances of TC and Related Elements in Stars of Type M, MS, and S
Abstract
Abundances of Co, Zr, Nb, and Tc relative to V have been derived for a sample of ten M and MS stars from 0.10 A/pixel and 0.04 A/pixel Reticon spectra. On a scale with log N(H) = 12.0 and log N(V) = 4.0, it is found that log N(Tc) is about 1.4 for M stars 1.0 MS stars with Tc. It has been suggested by Dominy and Wallerstein that the presence of Tc in M stars which show no enhancements of other s-process elements can be explained by a 'mini s-process'. Detailed calculations and the observed abundances and Tc and related elements presented in this study put this interpretation in doubt. The observations also fail to support the alternative hypothesis suggested by Malaney and Lattanzio that Tc is produced by the photofission of Th and U.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1991
- DOI:
- 10.1086/170649
- Bibcode:
- 1991ApJ...381..278V
- Keywords:
-
- M Stars;
- Nuclear Astrophysics;
- S Stars;
- Stellar Composition;
- Abundance;
- Asymptotic Giant Branch Stars;
- Chemical Composition;
- Late Stars;
- Astrophysics;
- NUCLEOSYNTHESIS;
- STARS: ABUNDANCES;
- STARS: LATE-TYPE;
- STARS: LONG-PERIOD VARIABLES;
- STARS: SEMIREGULAR VARIABLES